Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb0053a1c70c2629…

MALICIOUS

PDF

76.8 KB Created: 2021-09-18 09:07:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 4528ec44fde94fbc4d429046f8ad3a65 SHA-1: 02efe1977d5e995db9ebcc2d2a0582259234aa9e SHA-256: cb0053a1c70c2629d6d225243e8155d1ea70641e3e7bc035105ac8f6d378291a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was detected by ClamAV as Pdf.Phishing.Trojan and an ML classifier flagged it with high confidence. Heuristics indicate it functions as a link farm, pointing to multiple compromised WordPress upload directories and other disposable hosting sites. The embedded URLs suggest an attempt to redirect users to malicious content, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9901

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.gcsystem.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613ba12c63877---11272637012.pdf In PDF document text
    • http://sovaimm.it/userfiles/files/lekepubiwi.pdfIn PDF document text
    • http://karimeh.com/public/userfiles/file/xilasadegofafovoradotob.pdfIn PDF document text
    • http://airfa.it/userfiles/file/44376274076.pdfIn PDF document text
    • https://gangwontaxi.com/FileData/ckfinder/files/20210901_4A358EBBE0FDD7E3.pdfIn PDF document text
    • https://www.advids.co/wp-content/plugins/formcraft/file-upload/server/content/files/1613f913cea861---loteginusawonupasetaga.pdfIn PDF document text
    • http://gld-lining.com/user_img/files/gupugeno.pdfIn PDF document text
    • https://amt-alarmy.pl/userfiles/file/vutikudos.pdfIn PDF document text
    • http://movitecnic.fr/ressource/site-image/files/xosojorimavarekekasabi.pdfIn PDF document text
    • https://cfacgroup.com/uploads/FCK_files/file/96742140961.pdfIn PDF document text
    • http://big-blue-bus.com/pics/fotos/1/file/91609350415.pdfIn PDF document text
    • https://hometutorsdelhi.com/userfiles/files/67787242705.pdfIn PDF document text
    • http://burelomdo.com/ckfinder/userfiles/files/mijadebusumezanid.pdfIn PDF document text
    • https://braviengenharia.com.br/wp-content/plugins/super-forms/uploads/php/files/0tn5oh619rfhhiqbgih0u9oidu/nanusup.pdfIn PDF document text
    • http://fzcce.com/aimgs/uload/files/ralitawokufup.pdfIn PDF document text
    • https://fanaf.com/article_ressources/file/64788531182.pdfIn PDF document text
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140c048d1fa9---32048715570.pdfIn PDF document text
    • https://lose-weight.tw/upload/files/futinerex.pdfIn PDF document text
    • https://portsidestrategies.com/wp-content/plugins/super-forms/uploads/php/files/dcf84cefa5469f40649a30d336226991/sovaxobowifinesun.pdfIn PDF document text
    • https://www.agcontraincendios.es/ckfinder/userfiles/files/9033308743.pdfIn PDF document text
    • http://hunting.kg/userfiles/file/suwuvomunolovineruxaje.pdfIn PDF document text
    • https://dmitrovka-zn.ru/admin/ckfinder/userfiles/files/zidux.pdfIn PDF document text
    • http://erpos.sk/data/files/xetef.pdfIn PDF document text
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/13d4529bdc5f9cfab7bc742ac70bb82f/bozolezukexaziwimadan.pdfIn PDF document text
    • https://joyfool.art/wp-content/plugins/super-forms/uploads/php/files/47cd6f5fbc82dbba68a966d3d7ba018f/60587096405.pdfIn PDF document text
    • https://manhremhoangvan.vn/wp-content/uploads/files/nalotokumule.pdfIn PDF document text
    • http://gongin.humenia.com/upload/userfiles/2021/09/files/210909172444.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=ludo+game+malayalamPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c3f8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC3F8 19524 bytes
SHA-256: d7aa61df253776d57e60ab4f377f43fca95ae305fa1e9641a4f6bd7468766713
font_01_sfnt_off0000f68a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF68A 10200 bytes
SHA-256: b538c365d8212b15dddc54415aed97bddf659a084a35b680a9210de752b3879a
font_02_sfnt_off00010d3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D3A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1